Hello all,
What's the name for one of those knobs like you get on radio's for volume controls where it keeps turning and there's no stops? And how does it know which direction the knob was turned?
Thanks
gareth
Rotary encoders. Many methods, for example two offset optical disks.
-- Regards, Joerg http://www.analogconsultants.com/
Shaft encoder, also maybe gray code, do a wiki search
martin
Try "rotary encoder".
Specifically a quadrature rotary encoder. They have two outputs that each generate N pulses per revolution (N being determined by the resolution or sensitivity you desire). The two outputs are 90 degrees out of phase, so as the knob is spun, software can determine which direction it is spun by the phase relationship of the signals.
See
-- Paul Hovnanian paul@hovnanian.com ----------------------------------------------------------------------- Procrastinators: The leaders for tomorrow.
Its a rotary encoder.
You just count phased pulses from it. You can tell the direction from the phase the 2 pulses move.
For a really good picture, saw open a moving-ball mouse (pick one you never liked...). There's two in there, one for each of the (X and Y) axes.
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